George E. Berkey

Single-polarization fiber with a high extinction ratio.

An elliptical-core hole assisted single-polarization fiber was designed, fabricated, and characterized. Numerical modeling based on the vectorial Maxwell equation reveals the dependence of the single-polarization bandwidth on core delta and air-hole size. Several single-polarization fibers based on this design with their single-polarization operating windows centered between 0.9 and 1.5 microm were successfully demonstrated. A correlation between fiber birefringence and single-polarization operating bandwidth is qualitatively confirmed. A single-polarization bandwidth as high as 55 nm was observed. These fibers also show very high extinction ratios of 60 dB or higher at lengths much shorter than 1 m. Other properties such as the dependence on length of the single-polarization operating window were also measured.

High bandwidth single polarization fiber with elliptical central air hole

A novel design of single polarization fiber is presented. The structure of the fiber comprises an elliptical central air hole with depressed cladding surrounding the core. Parameters that affect the performance of the single polarization fiber in terms of the location of the single polarization operating window and single polarization bandwidth are analyzed. The analysis results in the identification of a fiber design that can yield a single polarization bandwidth as high as 240 nm around 1550 nm.

Broad-band dynamic dispersion compensation in nonlinear fiber-based device

In this paper we report on the design, numerical simulation and experimental testing of a novel dynamic dispersion compensation device based on self-phase modulation (SPM) in nonlinear fiber. The proposed all-fiber device is inherently simple and presents several unique advantages, most notably the potential for a broad-band operation covering all wave-length division multiplexing (WDM) channels of a system and the ability to address variable amounts of residual dispersion in each individual channel. Dynamic compensation ranges of up to 140 ps/nm for a single-stage and 240 ps/nm for a two-stage device are demonstrated with 40 Gb/s CS-RZ signal. It is shown that the device can operate with a minimum channel spacing of 200 GHz. For a two-stage device with inter-stage spectral filtering, simultaneous dynamic dispersion compensation (130 ps/nm for 1 dB penalty) and 2R regeneration (2 dB receiver sensitivity improvement) are demonstrated.

Negative slope dispersion compensating fibers

Two types of DC fibers are presented. The first is an improved high figure of merit (267) negative slope dispersion-compensating fiber intended for DC modules. Also presented is a type II DC fiber intended for field deployment that leads to total broadband dispersion compensation.

High-performance single-polarization optical fibers

This paper reviews recent progress and presents new designs and experimental results on single polarization (SP) fibers. The design concept for achieving SP propagation and approaches using either stress induced birefringence or hole-assisted geometrical birefringence for realizing single polarization fibers are described. Designs of hole-assisted SP fibers with either dual holes or a central hole are discussed in details. Effects of fiber parameters on SP fiber performance such as bandwidth, cutoff wavelength, mode field area are analyzed. Results on fabrication and characterization of dual-hole-assisted SP fibers are presented. SP operating windows centered at wavelength from 900 to 1600 mm with bandwidths from 18 to 55 nm are realized. Applications of SP fibers for single mode fiber lasers to produce linear polarized laser output are demonstrated with extinction ratio of 17-20 dB.

Novel fibers for dispersion-managed high-bit-rate systems

Summary form only given. Novel dispersion-managed fibers that minimize four-wave mixing (FWM) and other nonlinear effects with built-in dispersion compensation, large effective areas, and low dispersion slopes have been developed. These fibers are also expected to be flexible enough to allow upgrades in both wavelength-division multiplexing and time-division multiplexing approaches. Propagation and FWM efficiency models have been used to optimize the designs and evaluate the system advantages of these fibers.

Progress in high-power fiber lasers

We review current work on fiber laser systems at Corning. In particular, we describe design and performance of all-glass double-clad laser fibers, broad-area laser pumps, and pump coupling optics. We discuss our approaches using single-polarization fiber and low-nonlinearity photonic band gap fiber as technologies for developing the next generation of high-power fiber lasers.

Resonant ring fiber filters

We have studied structures where a concentric ring with an index higher than that of the cladding index is added to a conventional fiber core. The structure supports at least one additional symmetric mode with substantial power in the ring, besides the normal mode in the core. Within certain designed parameter regimes, the propagation constants of the lowest two symmetric modes cross at a certain wavelength. This is equivalent to saying that the LP01 mode can change from having more power in core to having more power in ring at a certain wavelength or vice versa. At this resonance, each of the two modes has substantial power in the core and the ring. This resonant nature of the structure creates a strong wavelength dependent mode field for LP01 and LP02 modes near the resonance wavelength. Filters based on this principle are demonstrated for the first time.

New high bandwidth single polarization fiber with elliptical central air hole

A new single polarization fiber with an elliptical central air hole is proposed. Effects of fiber design parameters on fiber performance are analyzed. Single polarization bandwidth as high as 240 nm is predicted.

Simultaneous multichannel pulse compression for broadband dynamic dispersion compensation

A novel scheme for multichannel dynamic dispersion compensation in an all-fiber device is proposed. Measurements on simultaneous pulse compression at 10 Gb/s with up to 8 channel show no significant crosstalk penalties and demonstrate the feasibility of the concept.